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authorGravatar Raphaël Monat <raphael.monat@ens-lyon.org>2017-10-03 20:45:13 +0200
committerGravatar Raphaël Monat <raphael.monat@ens-lyon.org>2017-10-03 20:45:13 +0200
commitb4b778f1a1657e0b65f5ac3fe466ca9a1e8d55d3 (patch)
tree7949298d0ea43c7d53116b3d2ca75f708ef15d88 /theories
parente664022ba1314d866e4e148d5f5f925654db0487 (diff)
Changed the statement of leb_not_le; shortened the proof
Diffstat (limited to 'theories')
-rw-r--r--theories/Arith/PeanoNat.v10
1 files changed, 2 insertions, 8 deletions
diff --git a/theories/Arith/PeanoNat.v b/theories/Arith/PeanoNat.v
index ffa56a6c3..95fd4cf86 100644
--- a/theories/Arith/PeanoNat.v
+++ b/theories/Arith/PeanoNat.v
@@ -172,15 +172,9 @@ Proof.
apply leb_le.
Qed.
-
-Lemma leb_not_le n m : (n <=? m) = false -> n > m.
+Lemma leb_not_le n m : (n <=? m) = false <-> ~n <= m.
Proof.
- revert m; induction n; destruct m; simpl; intros H_nm.
- - congruence.
- - congruence.
- - apply lt_succ_r, le_0_n.
- - specialize (IHn _ H_nm).
- now apply lt_succ_r in IHn.
+ now rewrite <- leb_le, <- not_true_iff_false.
Qed.
(** ** Decidability of equality over [nat]. *)